To connect a socket to a plug in an intended and correct way, it is known to design the socket and the plug to only allow the plug to be arranged in the socket in one way. A user that should arrange the plug in the socket thus has to see both the socket and the plug to be able to connect them.
A problem of this connection is for instance if a plug of a charger should be connected to a socket of a mobile phone and the lighting is poor. The user then has a problem of locating the socket and to orient the plug in a correct manner in relation to the socket.
Another problem is when a plug of an electronic device should be connected to the back side of a computer. The back side of a computer is often difficult to reach and even more difficult for the user to see.